Light Detectors Optical Sensors
741 Based Light Sensor: CdS photocell used for light/dark controlled relay
Basic Infrared Light Train Detection:
Battery Powered Sensor Detects Dangerous U Volt Radiation: 12/08/94 EDN-Design Ideas
Block Occupancy Detector Helper:
Dark / Light Activated Relay:
Day and Night Infrared Detection:
Demodulator Makes Low Cost Optical Tracker:
06/18/98 EDN-Design Ideas - Infrared to
Light Converter: This circuit converts
infrared light into sound. Modulated
Infrared light, like that ROM remote
controls, Infrared received by the
phototransistor and is amplified by the
LM386 IC.
Latching light detector is frugal with power
and parts: 09/26/2002 EDN - Design
Ideas / This idea demonstrates three uses
for the humble LED. The circuit in Figure 1a
forms a simple light detector that latches
and turns on an LED when the ambient light
exceeds a preset limit determined by
potentiometer P1. LED D1 is both the
indicator. Light Direction Sensor:
Light Intensity Sensor: Logarithmic
amplifier uses the log characteristic of PN
(diode, transistor) to implement logarithmic
function. The second transistor is used as
reference and with the PTK resistor
minimizes the dT/dV coefficient.
Light Pollution Meter : LED brightness
control circuit and a multimeter to compare
light levels to LED level.
Light Sensing RF Transmitter:
Light Sensor Adapter for Oscilloscope:
Light Sensor With Hysteresis:
LIGHT/DARK ACTIVATED RELAY: This is
actually two circuits a light activated
relay being the first and a dark activated
relay being the second, once again all
components and values are displayed in the
gif image.
Matched Diode Pair Improves Performance Of
Linear Optical Sensor : 05/27/02
Electronic Design - Ideas for Design /
Hand-marked cards for applications like
voting machines and meter readers often have
dark marks, light marks, erasures, or dirt.
Optical sensor needs no tweaking:
06/13/2002 EDN - Design Ideas / The
transfer gain of optical sensors spans a
16-to-1 ratio because of variations in the
LED, phototransistor, ambient temperature,
and optical path. The wide transfer-gain
variation complicates output-resistor
selection in dc-coupled circuits.
Photo detector Sorts Objects: 03/04/99
EDN-Design Ideas / PDF contains multiple
circuits - scroll to find this circuit.
Programmable Light Activated Relay:
Pulsed Sensor Extends Battery Life:
01/01/98 EDN-Design Ideas
RF Transmitter, Light Sensing:
Two LEDs Perform Rudimentary Spectral
Analysis: 09/01/94 EDN-Design Ideas
U Volt Sensitive Photodetector: